Phal crisis! 2 sick plants

1) Water DOES NOT cause root rot. Healthy tissue does not rot. Suffocation causes root death, and THEN it rots. Change your thinking from "over-watered" to "under-aired", and you'll quickly understand how to care for your plants better. A mounted plant will never have its root suffocated.

2) The loss of a small, lower leaf is not necessarily a cause for concern, but may be an indication that the plant is not getting enough water, either due to underwatering or having a compromised root system. The mix in that pot looks a bit too dense, as far as I can tell from the photo. Like Kelly, I'd recommend something a bit coarser, so you can keep the medium moist without fear of suffocating the roots.

 

The insect in the pot was most likely a springtail. They live in dirt, leaf litter, and the like that stays constantly damp. In terrariums, they're useful, as they scavenge on dead leaves and mold. In an orchid pot, they can mean it's being kept too damp.

When you water a phal, you'll notice that the roots turn from silvery-green to bright green. The plant shouldn't be watered again until after those roots turn back to silvery-green. I'd suggest a transparent pot for the potted one, as you can then easily see what color the roots are. As said above, watering once a week is generally good for phals, though be mindful of environmental conditions that could affect that. All of my plants are indoors, so they don't need more water in the summer, but some of them do want more in the winter because the central heating dries the air out. When you water, pour water through the pot until it runs out the bottom, to thoroughly reach all of the media. Really, that's what most plants want. Anything that doesn't want to be kept constantly moist generally wants to be watered deeply and allowed to dry out somewhat (usually not all the way) before the next watering. Helps promote healthy roots.

It's normal for phals to gradually lose their oldest leaves, which are the leaves at the bottom of the plant. New leaves come from the crown in the center. Make sure to never leave water standing in the crown, this can rot the plant very fast.

Phals are hardy. If it has at least one leaf, one root, and no crown rot, it has some chance of coming back. Both of yours have multiple leaves, multiple roots, and no evident rot, so they should both recover, if you can get them in conditions they like. The first one may be a smaller variety, some phals just aren't very large. Though if it hasn't bloomed yet, it may be a baby.